From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932769Ab1IBA3Z (ORCPT ); Thu, 1 Sep 2011 20:29:25 -0400 Received: from mail-gx0-f174.google.com ([209.85.161.174]:54887 "EHLO mail-gx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932740Ab1IBA3Z (ORCPT ); Thu, 1 Sep 2011 20:29:25 -0400 Date: Fri, 2 Sep 2011 09:29:17 +0900 From: Tejun Heo To: Ripduman Sohan Cc: linux-kernel@vger.kernel.org, peterz@infradead.org Subject: Re: [PATCH] workqueue: Restore cpus_allowed mask for sleeping workqueue rescue threads Message-ID: <20110902002917.GD2752@htj.dyndns.org> References: <1314884193-20454-1-git-send-email-ripduman.sohan@cl.cam.ac.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1314884193-20454-1-git-send-email-ripduman.sohan@cl.cam.ac.uk> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Thu, Sep 01, 2011 at 02:36:33PM +0100, Ripduman Sohan wrote: > Rescuer threads may be migrated (and are bound) to particular CPUs when > active. However, the allowed_cpus mask is not restored when they return > to sleep rendering inconsistent the presented and actual set of CPUs the > process may potentially run on. This patch fixes this oversight by > recording the allowed_cpus mask for rescuer threads when it enters the > rescuer_thread() main loop and restoring it every time the thread sleeps. Hmmm... so, currently, rescuer is left bound to the last cpu it worked on. Why is this a problem? Thanks. -- tejun